Ufolint

- updated ufoLib dependency to v2.3.1

- added license to Python wheels
- source formatting changes
- plistvalidators module: eliminated unnecessary assignment
- runner module: eliminated unnecessary import
- xmlvalidators module: eliminated unnecessary import

- updated ufoLib dependency to v2.2.1
- modified ufoLib.UFOReader instantiation in order to continue to support validation on UFO file reads after the ufoLib dependency changes
- modified ufoLib.glifLib.GlyphSet instantiation in order to continue to support validation on UFO file reads after the ufoLib dependency changes
- added Python 3.7 interpreter testing in CI testing settings files
- eliminated Python 3.4 interpreter testing in CI testing settings files

- updated ufoLib dependency to v2.1.1 (PR 6)
- updated release.sh shell script
- modified Appveyor CI testing settings

- added explicit ufolint labeling to test header and test success/fail strings to improve clarity of test that is being executed during multi-application CI testing

- initial release version